Antioxidant activities and key components of Chlorella water extracts

• Main Authors: Sun Tsai-Chien, 孫財前
• Other Authors: Vivian Min-Feng Lai
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/992ssw

碩士 === 靜宜大學 === 食品營養研究所 === 94 === Abstract This study was to investigate the antioxidant activities of Chlorella water extracts with various extraction conditions by the central composite design, where the independent variables were extraction temperature and time. The data were statistically analyzed with response surface method to find the optimal extraction condition for a better antioxidant activity. The results of antioxidation measurements indicated that all extracts showed a good DPPH-radical scavenging ability above 80% at 10 mg/mL. A greater scavenging rate constant presented at about 4050oC and 100oC according to the response surface analysis. The higher the temperature, the shorter was the period. The Fe2+-chelating ability increased with increasing the extract concentration. The rate constant k increased with the elevated temperature and maximized at 100oC for 1 hr (0.14 mL/mg). The Fe2+-reducing power rose with the increased extract concentration and maximized up to 0.135 mL/mg at 100oC for 1 hr and 40oC for 5 hr. The total phenol contents of the extracts at 80-100oC for about 4 hr were about 2.95 mg/g. The yield of water extracts increased to 18.0% with increasing temperature and for within 3 hr. Generally, the optimal extraction condition for Chlorella extracts with a higher antioxidant activity was 100oC and 1 hr. The results of HPLC-PDA analysis indicate that the 75% ethanol soluble of Chlorella water extracts exhibited a signal at 7.51 min and absorbance peaks at 219 and 274 nm, point to the possible presence of phenolic compounds. The monosaccharide compositions of Chlorella water extract at 100℃ for 1 hr were mainly composed of glucose (52.37±2.82%) and ribose (25.89±0.89%), totally for about 77%, and having a bimolecular distribution of F1 (24.97±0.6 kDa) and F2 (0.95±0.09 kDa).